From: Patrick McHardy <kaber@trash•net>
To: shemminger@osdl•org
Cc: netdev@vger•kernel.org, hadi@cyberus•ca
Subject: Re: [RFC IPROUTE 00/05]: Time cleanups
Date: Fri, 23 Jun 2006 20:09:18 +0200 [thread overview]
Message-ID: <449C2E4E.7050301@trash.net> (raw)
In-Reply-To: <20060623180642.13183.74864.sendpatchset@localhost.localdomain>
D'oh, got Stephen's address wrong. Please fix it (add 's' in front) in
replies to this thread.
Patrick McHardy wrote:
> I'm currently adding support for ktime as clocksource to the qdisc layer and
> in the course of doing that cleaned up the iproute time handling a bit to
> make it easier to use a different internal clock resultion and audit for
> integer overflows.
>
> Increasing iproutes internal clock resolution is necessary for all token bucket
> based schedulers to take advantage of a higher kernel clock resolution because
> the kernel only does lookups and additions/subtractions, which can never result
> in values that have a higher precision that those passed from userspace.
>
> The way I imagine it we have to keep the old clock sources around for userspace
> compatibility since they can't deal with the higher precision values. iproute is
> changed to use nsec internally and reads the kernel clock resulution from
> /proc/net/psched (third value, currently assumed to always be 10^6) to convert
> it's internal resolution to that of the kernel. With ktime as clocksource the
> kernel will report a resulution of 10^9. The downside is that distributors can't
> enable ktime unless they want to break compatibility with old iproute versions.
> Any better suggestions are welcome of course.
>
>
> tc/m_estimator.c | 4 ++--
> tc/m_police.c | 2 +-
> tc/q_cbq.c | 15 ++++++++-------
> tc/q_hfsc.c | 18 +++++++++---------
> tc/q_htb.c | 4 ++--
> tc/q_netem.c | 12 +++---------
> tc/q_tbf.c | 20 ++++++++++----------
> tc/tc_cbq.c | 8 ++++----
> tc/tc_core.c | 31 +++++++++++++++++++++++--------
> tc/tc_core.h | 9 +++++++--
> tc/tc_estimator.c | 2 +-
> tc/tc_red.c | 2 +-
> tc/tc_util.c | 33 +++++++++++++++++++--------------
> tc/tc_util.h | 7 ++++---
> 14 files changed, 94 insertions(+), 73 deletions(-)
>
> Patrick McHardy:
> [IPROUTE]: Use tc_calc_xmittime where appropriate
> [IPROUTE]: Introduce tc_calc_xmitsize and use where appropriate
> [IPROUTE]: Introduce TIME_UNITS_PER_SEC to represent internal clock resulution
> [IPROUTE]: Replace "usec" by "time" in function names
> [IPROUTE]: Add sprint_ticks() function and use in CBQ
next prev parent reply other threads:[~2006-06-23 18:09 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-06-23 18:06 [RFC IPROUTE 00/05]: Time cleanups Patrick McHardy
2006-06-23 18:06 ` [IPROUTE 01/05]: Use tc_calc_xmittime where appropriate Patrick McHardy
2006-06-23 18:28 ` Patrick McHardy
2006-06-23 18:06 ` [IPROUTE 02/05]: Introduce tc_calc_xmitsize and use " Patrick McHardy
2006-06-23 18:06 ` [IPROUTE 03/05]: Introduce TIME_UNITS_PER_SEC to represent internal clock resulution Patrick McHardy
2006-06-23 18:06 ` [IPROUTE 04/05]: Replace "usec" by "time" in function names Patrick McHardy
2006-06-23 18:06 ` [IPROUTE 05/05]: Add sprint_ticks() function and use in CBQ Patrick McHardy
2006-06-23 18:09 ` Patrick McHardy [this message]
2006-06-23 20:01 ` [RFC IPROUTE 00/05]: Time cleanups David Miller
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